Aronia Medik., commonly known as chokeberry, is a genus of deciduous, multistemmed, rosaceous shrubs native to eastern North America. Three species of chokeberry are commonly accepted, A. arbutifolia (L.) Pers., red chokeberry, A. melanocarpa (Michx.) Elliott, black chokeberry, and A. prunifolia (Marshall) Rehder, or purple chokeberry. In Europe, a fourth species of human origin is recognized as Aronia mitschurinii A.K.Skvortsov & Maitul. In North America this type of Aronia is described as cultivars of A. melanocarpa, including ‘Viking’, ‘Nero’, and ‘Aron’. This species is characterized by near homogeneity of the population, tetraploidy, and a distinct morphology with more robust stems, wider leaf blades, and larger fruits than wild populations of A. melanocarpa. It has been proposed that this genotype originated from Russian pomologist Ivan Michurin’s early 20th century experiments involving Aronia × Sorbus hybridization. In this study we used amplified fragment length polymorphic (AFLP) markers to elucidate the relationships of A. mitschurinii to wild North American Aronia, ×Sorbaronia C.K. Schneid, Sorbus L., and six additional genera from subtribe Pyrinae (Rosaceae). Data from seven primer combinations were interpreted by the NTSYSpc software package into a similarity matrix using Jaccard’s coefficient. Clustering of AFLP similarity data using the unweighted pair group method with arithmetic mean (UPGMA) identified A. mitschurinii as distinct from wild Aronia, grouping it close to ×Sorbaronia fallax C. K. Schneid. and ×Sorbaronia ‘Ivan’s Beauty’. Non-metric multidimensional scaling (nMDS) also demonstrated a relationship between A. mitschurinii, ×Sorbaronia fallax, a ×Sorbaronia × Aronia backcross and compound-leaved Sorbus.

Knowing the genome size is an important step towards deciding and planning for genome sequencing of a given species. Using flow cytometry, nuclear DNA content of Hydrastis canadensis was estimated, and genome size stability of its in vitro regenerated plantlets were assessed. The nuclear DNA content of H. canadensis was estimated to be 2.62 ± 0.020 pg/2C. This is the first report to estimate nuclear DNA content of H. canadensis; therefore this study provides valuable information that will facilitate genome sequencing and subsequent molecular studies of this economically important medicinal plant. Comparison of genome size between in vitro regenerated (explant source was from wild plants) and wild plants of H. canadensis did not reveal any significant difference (P B 0.05) in nuclear DNA content. This suggests that micropropagation of H. canadensis, even after numerous sub-culturing and long-term culture periods produced in vitro plantlets with a stable genome size. These results provide further evidence that micropropagation techniques have the potential to be used as a source of planting stock, along with seeds, for restoring locally threatened H. canadensis wild populations and for commercial cultivation to supply the growing herbal market.

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These new markers will provide tools for examining genetic relatedness of B. thunbergii plants in the native and invasive range, including phylogeographic studies and assessment of rapid evolution in the invasive range. These markers may also provide tools for examining hybridization with other related species in the invasive range.